Harvey j



@uiten tstrs gaten-t @fing HARVEY J. HARWOOD-AND WILLIAM H. MICKIE1` 0E-UTIOA, NEWYORK, .ASSIGNORS T HARVEY J. HARWOOD AND JOHN F. SEYMOUR, OF SAME PLACE.

Leiters Patent No. 72,490, dated 'December 24, 1867.

IMPROVED MACHINE FOR THREADING SGREWS.

TO ALL WHOM IT MAY CONCERN:

Be it known that we, HARVEY .1'. HARWOOD and WILLIAM H. MICKLE, both of Utica, county of Oneida, and

State of New York, have invented certain new and useful Improvements in Machinery for Making WoodScrcws;

andwe do hereby declare that the following is a full, clear, and exact description of the construction and operation thereof, reference being had to the annexed drawings, makinga part of thisspeciiication, in' which the gures are all reduced in size.

Figure 1 is a perspective v iew. l Figure 2 is a horizontal section, made on a plane with the upper surfaces of the vdies A and B, tig. 1

showing a perspective of the double crank E and its connections.

vFigure 3 is a horizontal section through, on the plane of the uppersurface ot'l L, fig. 1.

Figure 4 is a transverse section through, on a line between'c and m, iig. 1.

Figure 5 is a longitudinal elevation of die A, figs. 1, 2,. and 3.

Figure 6 is a sectional view of the guides 7c, Z, and m, iig. 1', made lengthwise between dies A and B.

.To enable others skilled in the art to make and use our invention, wewill proceed to describe its construction and operation. A i

We construct our machine with dies, soformed as to make screwsv of the shape desired. The following is the form of die we prefer: in figs. 4 and 5, they have grooves cut on the faces that are toward each other, leaving the metal between the vgrooves in the-form of threads, said threads to be of the size an'd shape of the space intended to be between two contiguous coils of the thread on the blank to be threaded, or of the size and shape of the space intended to be `between two contiguousthreads of the blank to be threaded. Said thread should form, with the edge ofthe die, an angle equal to the angle of the thread or threads intended for the blank, except the part that forms the point ofthe screw, (the point of thefscrew is formed on the raised part of the dies,) which part curves so as to increase said angle, thereby increasing the pitch ot' the screw at the point which enables its lips to more readily enter wood. The edge of the thread of the die, as viewed in a transverse section ofthe die, (fig. 4,)7should be of the desired form of core for the intended screws (which is the same in Charles R. Gardners die, patented August 12, 1856.) We make our dies where 'we form the lip or lips of the screws-(commonly called the point of theA screw) so deep as not to reduce the diameter of the screw in that portion. We commonly make it of its greatest diameter there, which is not the case with any other dies. We sometimesmake the dies so as' to form a screw tapered for one or two threads at the entering end. The dies andB are channelled beyond the part which forms the point of the screw, to allow the refuse Ametal to escape. The dies A and B are each double dies, and can be made of one or more pieces each (figs. 4 and 5.)

We operate the dies A and B, figs. 1,2, and 4, by a double crank, E, tig. 2, which 'is connected by pitmen C and D', and imparts a reciprocating movement to each die, and causes them to move in opposite directions,

und each die to move the same distance,.so when a blank is being formed into a screw, it rotates upon its own axis and does not travel. The same movements can beohtaiued with screws or racks and pinion. The guides k, Z, and m, figs. 1, 2, 3, 4, and .6, are to hold the blank at right angles to thc edge of the dies while it is being l threaded. The guide m,.iig. 1, is attached to the frame. The guides Z: and Z are so attached that they can be moved to und from m. o is an arm et k, and n is. an arm of Z. o and n cover the blank while it is being threaded, so that when 7c is opened, it uncovers the place for the-blank to enter betweenZand m,- and whenZ is opened, it uncovers the place for the blank to enter between m and Zr. The guides 7c and Z, g. 1, are opened and shut by the pin or`tud z', in die A, gs. 2 and 3, acting upon the cams or inclined planes on catches rand and s, iig. 3. Catches r and .s are connected to Ak and Z. The pin or stud t' enters the opening in 1'. Passing along the inclined plane, it raises-rl out of the notch in m; then it presses against the bottom ofthe opening in r, thereby crowding c back, (It being attached to r,) so, when A has completed ,its stroke in that direction, the guide Zr is far enough from m to allow the screw-head to fall through the opening between 7c and m, and while it is in said position, there are depressions opposite each other, on the faces of the dies A and B, large enough to allow the screw-head to pass between them. There is also an aperture in-the bottom of the frame, under said depressions, and in line therewith, so that the screw can fall through theV machine. At the same time, on the other side of m', the openingr between m and Z being uncovered,.a blank is inserted in said opening. 'Noivthe dies change their motion, and the pin or stud z' pressesv against the cam a, and carries r `and'its appurtenances along, until the guide c reaches guide m, then the catch r is pressed-into the notch in m by the pin z'acting upon the cam a on 1'. At this time lrib 5 on die A comes travelling backof catch r, and holds itdoivnuntil pin or stud z' returns. The pin or stud z' travels along with A until reaches catch 8,'1rhen the same or a similar operation to that performed at `catch r is repeated.' The same or a similar operation; isrepeated each stroke. There are two slight depressions i'n die A, at 6 and 7, and one heavy depression at 8, figs. 2 and 5. B hns a slight depression opposite depression 8 on A, figs. 2` and 5, and heavyfdeprcssions opposite G and 7 on A. When the dies A and Bare at the end of their movements in either direction, the large deruess'ion', 8, -in the centre of die A, is opposite one of the large depressions in the ends of B at the-same time the small depression in the centre of-die B isopposite one of the small depressions in the ends of die And while the dies are in this position, the blank to be threaded is inserted in the opening formed by-,the small depressions. i Then, as the crank E is turned one-halt` of a revolution, the blank'is rotated on its own axis, and threaded by the desA and B. While being threaded,- the blank is held at right angles with the face'of the dies by thc guides 7c, Z, and m, figs. l and 6.

We do not broadly claim reciprocating dies, but

What We do claim as our invention, and de'sire to-secure by Letters Patent, is

1. We claim theV combination oi` the reciprocating dies A and B, and-guides k, l, and m.

2. We elaimthe construction of the curved part ofthe threads' on the die that forms'thepoint of therscrew of increased pitch, as described. l

3. We claim the channels v v o, in the dies A and B, that extend beyond the part of the die that forms the point of the screw. I A

4. We claim the general arrangement of the parts whereby the dies are enabled to operate upon two screws during cach revolution of the crank E. p Y

5. We claim the opening and closing of the guides c, Z, and m, in the manner and by means substantially as described. y

6. We claim'the guides 7c and Z, and their arms o and n, arrangedin the manner and for the purpose described.

H. HARWOOD, WILLIAM H. MICKL Witnesses:

M. M. JONES, C. VSAU'rcrnn. 

